GaN-based laser diodes （LDs） with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition （MOCVD）. Electroluminescence spectra of the fabricated LDs show that the LDs from so...GaN-based laser diodes （LDs） with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition （MOCVD）. Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser. The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells （MQWs） and super-lattices between LDs that succeed and fail to emit laser. However, the cathodoluminescence （CL） measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs. Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs.展开更多
Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane Ga...Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [1100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.展开更多
The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell...The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell, photodiode （PD）, and magnetic coil into a cuboid metal package with a volume of about 2.8 cm3. In this physics package, the critical component, 87Rb vapor cell, is batch-fabricated based on MEMS technology and in-situ chemical reaction method. Pt heater and thermistors are integrated in the physics package. A PTFE pillar is used to support the optical elements in the physics package, in order to reduce the power dissipation. The optical absorption spectrum of 87Rb D1 line and the microwave frequency correction signal are successfully observed while connecting the package with the servo circuit system. Using the above mentioned packaging solution, a CSAC with short-term frequency stability of about 7 × 10^-10τ-1/2 has been successfully achieved, which demonstrates that this physics package would become one promising solution for the CSAC.展开更多
第3代半导体材料是指带隙宽度明显大于硅（S i）（1.1e V）和砷化镓（G a A s）（1.4e V）的宽禁带半导体材料。它具备禁带宽度大、击穿电场高、热导率大、电子饱和漂移速率高、抗辐射能力强等优越性能，是固态光源、下一代射频和电力...第3代半导体材料是指带隙宽度明显大于硅（S i）（1.1e V）和砷化镓（G a A s）（1.4e V）的宽禁带半导体材料。它具备禁带宽度大、击穿电场高、热导率大、电子饱和漂移速率高、抗辐射能力强等优越性能，是固态光源、下一代射频和电力电子器件的“核心”，在半导体照明、消费类电子、5G移动通信、新能源汽车、智能电网、轨道交通等领域有广阔的应用前景，有望突破传统半导体技术的瓶颈，与第1代、第2代半导体技术互补，对节能减排、产业转型升级、催生新的经济增长点发挥重要作用，正在成为全球半导体产业新的战略高地。我国在半导体照明方面已经形成完整的产业链和一定的产业规模，成为全球发展最快的区域，为第3代半导体在其他领域的应用奠定了良好的基础。但我国在电力电子、通讯等领域的研发和产业化与国外差距较大，需要加大研发投入，建立体制机制创新的研发创新和科技服务平台，构建立足地方、带动全国、引领世界的跨学科、跨行业、跨区域的第3代半导体创新价值链，重塑全球半导体产业发展格局。展开更多
With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the produc...With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the products of different enterprises cannot interchange with each other, restraining the development of the whole industry due to the large-scale production problem. The alliance standard CSA 016-2013 has been approved as a national standard project, paving the way for the orderly development of LED industry. Interpreting the CSA 016 standard, the paper expounds on the technical requirements for interchangeable interface in the optical, mechanical, electrical and thermal aspects.展开更多
The initial growth conditions of a 100 nm thick GaN layer and Mg-surfactant on the quality of the GaN epilayer grown on a 6H-SiC substrate by metal-organic vapor phase epitaxy have been investigated in this research. ...The initial growth conditions of a 100 nm thick GaN layer and Mg-surfactant on the quality of the GaN epilayer grown on a 6H-SiC substrate by metal-organic vapor phase epitaxy have been investigated in this research. Experimental results have shown that a high V/III ratio and the initially low growth rate of the GaN layer are favorable for two-dimension growth and surface morphology of GaN and the formation of a smoother growth surface. Mg-surfactant occurring during GaN growth can reduce the dislocations density of the GaN epilayer but increase the surface RMS, which are attributed to the change of growth mode.展开更多
基金Social Science and Technology Development Project in Dong Guan-Model LED Light Source for Plant GrowthThe National Natural Science Foundation of Guangdong+4 种基金China(Grant No.2015A030312011)The Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2014KF17)Changzhou Major Public Technology Platform Construction Project(CZ2013001)Guangdong Province Industry-University-Research Cooperation Project(2013B090500004)Dong Guan City Industry-University-Research Cooperation Project(2014509130207)
基金Supported by the National Natural Science Foundation of China under Grant Nos 60577030 and 60776041, and the National Key Basic Research Special Foundation of China under Grant Nos TG2007CB307004 and 2006CB921607.
文摘GaN-based laser diodes （LDs） with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition （MOCVD）. Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser. The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells （MQWs） and super-lattices between LDs that succeed and fail to emit laser. However, the cathodoluminescence （CL） measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs. Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60676032, 60577030 and 60476028)the National Basic Research Program of China (Grant No. 2007CB307004)the National Science Foundation for Post-doctoral Scientists of China (Grant No. 20060400018)
文摘Non-polar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [1100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.
基金supported by the Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KGCX2-YW-143)
文摘The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell, photodiode （PD）, and magnetic coil into a cuboid metal package with a volume of about 2.8 cm3. In this physics package, the critical component, 87Rb vapor cell, is batch-fabricated based on MEMS technology and in-situ chemical reaction method. Pt heater and thermistors are integrated in the physics package. A PTFE pillar is used to support the optical elements in the physics package, in order to reduce the power dissipation. The optical absorption spectrum of 87Rb D1 line and the microwave frequency correction signal are successfully observed while connecting the package with the servo circuit system. Using the above mentioned packaging solution, a CSAC with short-term frequency stability of about 7 × 10^-10τ-1/2 has been successfully achieved, which demonstrates that this physics package would become one promising solution for the CSAC.
文摘第3代半导体材料是指带隙宽度明显大于硅（S i）（1.1e V）和砷化镓（G a A s）（1.4e V）的宽禁带半导体材料。它具备禁带宽度大、击穿电场高、热导率大、电子饱和漂移速率高、抗辐射能力强等优越性能，是固态光源、下一代射频和电力电子器件的“核心”，在半导体照明、消费类电子、5G移动通信、新能源汽车、智能电网、轨道交通等领域有广阔的应用前景，有望突破传统半导体技术的瓶颈，与第1代、第2代半导体技术互补，对节能减排、产业转型升级、催生新的经济增长点发挥重要作用，正在成为全球半导体产业新的战略高地。我国在半导体照明方面已经形成完整的产业链和一定的产业规模，成为全球发展最快的区域，为第3代半导体在其他领域的应用奠定了良好的基础。但我国在电力电子、通讯等领域的研发和产业化与国外差距较大，需要加大研发投入，建立体制机制创新的研发创新和科技服务平台，构建立足地方、带动全国、引领世界的跨学科、跨行业、跨区域的第3代半导体创新价值链，重塑全球半导体产业发展格局。
文摘With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the products of different enterprises cannot interchange with each other, restraining the development of the whole industry due to the large-scale production problem. The alliance standard CSA 016-2013 has been approved as a national standard project, paving the way for the orderly development of LED industry. Interpreting the CSA 016 standard, the paper expounds on the technical requirements for interchangeable interface in the optical, mechanical, electrical and thermal aspects.
基金Project supported by the National High Technology Research and Development Program of China(No.2012AA03A115)
文摘The initial growth conditions of a 100 nm thick GaN layer and Mg-surfactant on the quality of the GaN epilayer grown on a 6H-SiC substrate by metal-organic vapor phase epitaxy have been investigated in this research. Experimental results have shown that a high V/III ratio and the initially low growth rate of the GaN layer are favorable for two-dimension growth and surface morphology of GaN and the formation of a smoother growth surface. Mg-surfactant occurring during GaN growth can reduce the dislocations density of the GaN epilayer but increase the surface RMS, which are attributed to the change of growth mode.
